There are a number of situations in which it may be desirable to cultivate plants without having to use soil. For example, during the colder months of the year, some gardeners begin growing seedlings indoors in anticipation of spring. This process is more simple and sanitary when soil is not used.
Growing mediums other than soil may be used to germinate seeds. One popular growing medium is rockwool. Rockwool is used extensively for hydroponic growing systems. Rockwool is made by melting a combination of rock and sand and spinning the mixture. This results in fibres that may be formed into different shapes and sizes.
Rockwool absorbs and maintains water. Further, rockwool is porous and thus retains oxygen. As a result, plants that grow in rockwool have healthy root systems. Finally, rockwool can be formed into a number of shapes and sizes. Frequently, rockwool fibres are compressed into cubes.
Before using a rockwool cube, the cube must be treated by soaking it in a nutrient solution to adjust its pH level. Further, once seeds or seedlings are placed in rockwool, the rockwool is periodically watered. Therefore, rockwool is moist when in use.
The moisture of rockwool cubes creates some difficulties for gardeners. Specifically, when rockwool is exposed to the light that is normally used for indoor germination and cultivation of plants, algae forms on the surface of the moist rockwool cubes. Such algae attracts insects such as fungus gnats and shoreflies. Further, when algae decays and dies, it can become detrimental to plants since it may invite bacteria and viruses. Algae can even compete with the plants being grown for oxygen, which is necessary for nutrient uptake.
To prevent the growth of algae on rockwool, it is necessary to deprive the algae of light. Algae flourishes in wet, well lit locations and depriving it of light prevents photosynthesis.
Various solutions have been proposed for covering rockwool cubes to prevent the growth of algae. However, previously disclosed rockwool cube covers suffer from a number of disadvantages. First, such covers limit the circulation of oxygen, thus creating an anaerobic environment. This inhibits nutrient uptake by the plant. Further, some previously disclosed cube covers are simply sheets of plastic that are placed above the cube and frequently engage the surface of the cube, thus further inhibiting the circulation of oxygen. Finally, previously disclosed cube covers are not durable.